This invention relates to an electric shower-waste pump and control unit. Self-contained shower-waste pump and control units are known, and can be obtained from Autumn (UK) Limited of Ashton-under-Lyne, Lancashire, United Kingdom, Impey (UK) Limited of Ilton, Somerset, United Kingdom, and Digital Pumps Limited of Blackpool, Lancashire, United Kingdom.
Prior art examples of such units 1 are shown in FIGS. 1 to 3. Each unit 1 comprises a water-tightly sealable housing 2 in which is housed a shower-waste pump 3 and appropriate electronic control circuitry 4. An external mains AC electricity supply, typically of 230 or 240 volts, is connected via a connector 5 to a power transformer 6 forming part of the electronic control circuitry within the housing. The power transformer converts the mains voltage to a lower voltage suitable for operating the pump and the control circuitry.
Such a unit 1 is typically connected to a shower 7 as shown in FIG. 4. The shower head 8 is provided above a shower tray 9 having a waste outlet 10. The shower head is connected to a, typically wall-mounted, shower unit 11, which in turn is connected to a mains water supply 12.
A flow sensor 13 or sensors is/are connected to the shower-waste pump and control unit 1 and monitor operation of the shower unit. The shower-waste pump and control unit itself is connected to a mains power supply 14.
The waste outlet of the shower tray is connected to one port 15 of the pump 3 of the shower-waste pump and control unit, and another port 16 of the pump discharges to a drain pipe 17 and then to a soil pipe 18 of the building.
The problem with such prior art arrangements is that, should the pump leak, the water-tightly sealed box can fill with water. This leads to direct contact with the electrically energised control circuitry. The water leaking from the pump thus forms a conduction path back to the floor of the shower tray or base presenting a serious and potentially fatal risk of electrocution.
The pump utilised in such units is often of a diaphragm variety, and this kind of pump is well known to fail through diaphragm wear. Leakage of water through a worn diaphragm frequently occurs. The water can thus pass out of a pump housing and into the housing of the unit by flowing through an air vent hole intentionally provided for venting air from behind the diaphragm.
This is a known problem which has not heretobefore been addressed, and the present invention seeks to provide a solution.